Senate Democratic Leader Harry Reid is slated to kick off the marathon gabfest at about 10pm Irish time with the final address expected to end about 15 hours later, at 1pm Irish tune on Tuesday.

Thirty of the Senate's 53 Democrats, plus the two independents who caucus with them, have signed up to participate. The White House said it will post live tweets during the overnight session under the hashtag #up4climate.

"It's time for Congress to wake up and get serious about addressing this issue," said Senator Sheldon Whitehouse of Rhode Island, a leader of the Climate Action Task Force that organized the event.

Whitehouse told reporters that the talkathon was the "opening salvo" to a more coordinated, years-long push for comprehensive climate legislation.

"We hope that by staying up all night ... we will signal a new dawn of climate change action in Congress," added Senator Ed Markey of Massachusetts.

Many scientists attribute rising temperatures and some extreme weather events worldwide to the increased release of carbon dioxide from burning fossil fuels.

They fear that as carbon dioxide accumulates in the atmosphere there will be more severe weather, including floods, hurricanes, tornadoes and drought.

After failing to make climate change a priority in his first term, and with no major climate legislation expected form a deeply divided Congress, Democratic President Barack Obama is addressing the issue by wielding his executive powers.

Democrats, meanwhile, hope to make it an issue that will rally their liberal base for November's midterm congressional elections.

Not signed on for Monday's event are four Democratic senators regarded as the most vulnerable in November: Mary Landrieu of Louisiana, Kay Hagan of North Carolina, Mark Begich of Alaska, and Mark Pryor of Arkansas.

Early indications were that none of the 45 Republicans in the Senate would participate either.

Republican lawmakers have been among the leading opponents of efforts to address climate change.

Shortly before Senate Democrats began their offensive, Republican Senator Jeff Sessions of Alabama rose to say that many are misinformed about the threat of global warming.

"There has been a lot of exaggeration, there has been a lot of hype," Sessions said. "It's time for us to be a bit more cautious and to be less alarmist and to focus more on the science of the situation."

McConnell has defended Kentucky's coal industry from moves by the Obama administration to limit emissions from power plants, which are blamed for contributing to global warming.

His comments drew a letter on Friday from Whitehouse and Democratic Representative Henry Waxman of California.

"Your statements are inconsistent with the overwhelming scientific consensus that climate change is occurring, is caused primarily by humans, and will have serious impacts if unchecked," the Democrats wrote.

Obama adviser John Podesta, a longtime advocate of climate action, joined the social media site Twitter on Monday ahead of the all-nighter.

In just his second message, Podesta tweeted: "Climate deniers have closed their eyes (and minds) to what's happening to our planet. Stay #Up4Climate all night tonight with @SenateDems."